| Summary: | 碩士 === 國立臺灣大學 === 電信工程學研究所 === 93 === The movement of a video camera caused by hand jiggle introduces jerky image motion that is often annoying to human eyes. The problem can be solved by using an image stabilization system to compensate for the hand motion. As opposed to optical image stabilization which uses gyro-sensors to detect hand motion and shifts a corrective lens inside the lens system (or alternatively shifts the image sensor while keeping the lens fixed) , digital image stabilization detects the induced image motion based on the video data and shifts the image display window accordingly to compensate for the hand motion. For many digital video camera designs, digital image stabilization is a cost effective solution and is the subject of discussion in this thesis.
A digital image stabilization system that can reduce inter-frame hand-shaking movement and smooth the intentional camera movement in a video sequence is proposed. The video sequence is processed to estimate the local motion vectors by block-based motion estimation and to obtain the global motion vector by clustering. The global motion vector between frames is real-time low-pass filtered to remove high frequency motion component caused by hand-shaking. A simplified stabilization algorithm facilitates the implementation on BF561, a DSP processor of Analog Device. For a digital video camera, digital image stabilization system and video coder are two important components, which both require motion information of the captured image sequence to perform their respective tasks. Since motion estimation is a computationally intensive operation, we propose three schemes for integrating the electronic image stabilization system with the video coder. The technical issues involved in the integration are discussed, and the simulation results are shown to illustrate the effectiveness of the integration schemes.
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